It is a bit weird to run an SSD in a USB 2.0 enclosure.
I never get beyond 35MB on mine and if I attach it on the hub instead of directly at a port it isn't even that. Only 25-30.
40MB/s is an incredible speed for USB 2.0 and about the best you can possibly expect. I would be proud of those controllers on both ends.

MacRumors attracts a broad audience
of both consumers and professionals interested in
the latest technologies and products. We also boast an active community focused on
purchasing decisions and technical aspects of the iPhone, iPod, iPad, and Mac platforms.